docs: def write(self, section, option, value):
          """Write to file.
  
          Parameters
          ----------
          section : string
              Section.
          option : string
              Option.
          value : string
              Value.
          """
          self.config.read(self.filepath)
          string = tidy_headers._parse_item.item2string(value, sep=", ")
          self.config.set(section, option, string)
          with open(self.filepath, "w") as f:
              self.config.write(f)